U.S. Pat. No. 8,041,016 (“016”) teaches the above by employing telephony, as opposed to e.g. in WO 00/35178 and U.S. Pat. No. 7,509,119 where a person should be in advance registered or preauthorized, and which tends to drastically reduce the number of possible users or visitors that may at any time successfully request access.
Where a stated user is not preauthorized for access either at an access point or by an authorized party, some means for the user to be in real time securely authorized and given access must be provided. Should the access point have a telephone or data network connection of its own, this is not a problem and can be solved by many available and known logging in password etc. authentication protocols. The authorized party is then contacted by the user and can evaluate and decide whether to give access or not; effectuating access by making a voice or message telephone call to the access point.
Where an access point does not have its own network connection and also the user is not preauthorized, U.S. Pat. No. 8,041,016 discusses an embodiment wherein a user's mobile telephone connected to an authorized party can relay information between that party and an access point; and wherein the stated communication format can be acoustics, IR and/or RF.
Whereas IR and RF presently are not available as standard short range communication formats with all common mobile phones e.g. NFC isn't yet available with iPhones, IR ports are by now mostly phased out; one may require some singular configuration, acoustics are immediately available at all telephones; and which accordingly has been used for data transfer for a long time. See U.S. Pat. Nos. 4,511,970; 5,157,717; 7,509,119 and 7,835,942, for example.
However and especially in noisy places, such transfer can be compromised and complicated by imperfect alignment or too low volume of either an access point or a mobile phone, slow transmission rate etc., which may tend to render acoustic coupling less suited here for secure transfer of larger data sets.